Evaporator



March 14, 1939. B. s. HUGHES EVAPORATQR 2 Sheets-Sheet l Filed Sept. 15, 1957 y Q-u/ QQW fl orng March 14, 1939.

o oo 163 O o o o hi o o o eocoooooooo 00000000090 9000000000 oooooooooooo Oooooo 5 900000000 B.'S. HUGHES V EVAPORATOR Filed Sept. 15, 1957 2 Shet's-Sheet 2 Patented Mar. 14, 1939 PATENT OFFICE EVAPORATOR Burton S. Hughes, Buffalo, N. Y., assignor to Zaremba Company, Buffalo, N. Y., a corporation of Maine Application September 15, 1937. Serial No. 164,021

1 Claim.

This invention relates to certain new and useful improvements in evaporators for concentrating solutions.

One of its objects is the provision of a multiple-pass evaporator for concentrating solutions which is so designed and constructed as to effectually utilize the heating surfaces thereof to obtain a maximum rate of evaporation and promote the concentration of the solution to a high density in a. minimum period of time.

Another object of the invention is to provide an evaporator of this character which is simple, compact and inexpensive in construction, which requires a minimum of floor space for its installation, and which is continuous, positive and eflicient in operation.

A further object is to provide a multiple-pass evaporator which is designed to operate at a uniform rate, which produces products of high 2 grade and quality, and which employs but a minimum of heating surface to produce the desired high density product.

In the accompanying drawings:

Figure 1 is a central longitudinal section of the evaporator embodying my improvements. Figures 2, 3 and 4 are horizontal sections taken on the correspondingly numbered lines in Fig.- ure 1.

Similar characters of referenceindicate corresponding parts throughout the several views.

In the preferred embodiment of the invention shown in the drawings, my improved evaporator comprises a steam chest or chamber ill in which are arranged a plurality of vertical tubes ll wherein the juice or solution is boiled and which extend through and are expanded into upper and lower tube-sheets l2 and I3, respectively. At its bottom the steam chest is provided with a liquor box l4 having a plurality of hand-holes l5 normally closed by suitable covers and through which the tubes II may be inspected when desired. At its upper end the steam chest is provided with a vapor box I6 having a cover I! at its top which is normally sealed in place by hinged bolts l8 or like devices and which may be lifted and swung to one side, when it is desired to inspect or have access to the tubes II,

by a suitable overhangingcrane i9. Steam is admitted to the steam chest through a steam inlet 20, and at its lower end it is providedwith a condensate drain 2|. The liquor box M has a drain outlet 22 through which the concentrated liquor is removed, while the thin liquor to be 55 concentrated is introduced into the central or middle section of the vapor box i6 through an inlet 23.

Communicating with the vapor box IE of the steam chest in is a vapor body or tank 24 of substantially cylindrical shape, the lower portion 5 of this body' constituting a receiving chamber 25 for the liquid and vapor delivered thereto from the vapor box and the upper portion 01' said body constituting and being shaped to provide a centrifugal separator including an outer annular 1o chamber 26 formed by a concentric wall 21 spaced from the outer wall of the vapor body. This concentric wall forms a vapor-receiving hood 28 in direct open communication with the receiving chamber 25 of the vapor body and its 15 wall 21 has an outlet or opening 29 through which the vaporpasses into the annular chamber 26, the latter discharging at its opposite end into the vapor outlet 30 provided adjacent the upper end of the vapor body. As shown in Figure 20 3, the concentric wall 2'! is provided with an extension 3| which extends across the annular chamber 26 and separates the hood-outlet 29 from the body-outlet 30, whereby the vapdr after entering the annular chamber travels in a clrcug5 lar course before being discharged from the vapor body into a condenser or succeeding efiect evaporator not shown.

The vapor and liquid from the vapor box I8 is introduced into the lower portion oi'the vapor body 24 through a passage 32 connecting such parts, as shown in Figure 1. The liquor box I4 and the vapor box-l6 of the steam chest III, as well as the lower chamber 25 01' the vapor body are transversely divided or separated into a plu- 35 rality of companion compartments,-three being shown in the drawings, for effecting and controlling the passage or circulation of the liquid being concentrated through the evaporator so as to promote the concentration of the liquid to the 40 required density in a minimum period oi! time. To this end, the liquor box I4 is provided at opposite sides of its center with two upright transverse partitions 33 providing companion central and side compartments 34, 35 and 36, respectively, and the vapor box IE of the steam chest and the communicating chamber 25 of the vapor body 24 are provided with similar partitions 31 which are substantially in the same planesas the liquor box partitions 33 and which may either be in one piece, that is, extending across the vapor box l6 and the chamber 25 and the-connecting or intercommunicating passage 32, or they may be made in alining sections and joined at their abutting ends to produce, in effect, continuous partitions. Those portions of the partitions 31 extending across the vapor box l6 of the steam chest provide companion central and side compartments 38, 39 and 40, and the portions there of extending across the chamber of the vapor body provide companion compartments 4|, 42 and 43 which communicate, respectively, through the passage 32 with the corresponding compartments of the vapor box H5. The liquor inlet 23 is arranged so as to introduce the liquor into the central compartment 36 of the vapor box. It will be noted in Figure 2 that the portions 44 of the partitions 31 preferably diverge outwardly in the vapor body 24 from a point substantially centrally of the latter.

The respective compartments 4| 42 and 43 of the vapor body 24 communicate with the companion compartments 34, and 36 of the liquor box |4 through the medium of companion pipes or conduits 45, 46 and 41, respectively, which connect the bottom of the vapor body with the liquor box M in the manner shown in Figure 1, these conduits completing the circulation system of the evaporator. Connecting the pipe 45 with the pipe 46 is a branch pipe 48 and connecting the pipe 46 with the pipe 41 is a branch pipe 49, whereby during the circulation of the solution through the evaporator it is by-passed through the aforesaid branch connections to successively pass through the stages provided by the multicompartment structure heretofore described.

Extending into the vapor body 24 between its lower and upper chambers 25- and 26, and immediately over the communicating passage 32 connecting said body with the liquor box I4 of the steam chest, is a bafile or deflector 56 which terminates at its inner end in a downwardly-sloping extension 5| for deflecting the liquid downwardly into thereceiving chamber compartments 4|, 42 and 43 of the vapor bo'dy, while the vapor carried therewith rises and passes into the centrifugal separating chamber 26 thereof. This deflector extends across the multiple compartments of the vapor body and intersects the adjoining top portions of the partitions 31.

If desired, a water spray pipe 52 may be positioned in the upper end of the annular chamber 26 of the centrifugal separator portion of the vapor body 24. Also, a drain pipe 53 may be provided connecting the chamber 26 with the bottom of the vapor body 24.

In operation, the solution or thin liquor to be concentrated is introduced into the central compartment 38 of the vapor box |6 through the inlet 23, where it mingles with the mixture of steam and liquor ascending through the tubes I located in the central section of the steam chest l6 and opening into said compartment 38, and thence travels through the passage 32 into the communicating central compartment 4| of the vapor body 24. The liquid then flows into the central compartment 4| of the chamber 25, while the vapor issuing therefrom rises into the upper portion of the vapor body and passes through the centrifugal separating chamber 26 thereof to a condenser or the like. From the central compartment 4| of the chamber 25 the liquor flows downwardly through the middle pipe 45 into the central compartment 34 of the liquor box I4 and thence upwardly through the tubes on which it is heated by the surrounding steam chest to evaporate the water contained therein and concentrate the solution. As the pipe 45 is connected by a branch pipe 48 with the pipe 46, the solution also enters the latter and flows into the communicating compartment 3501' the liquor box and then circulates upwardly forla second pass through the alining section of tubes into the companion vapor box compartment 39, from which it flows into the alining compartment" in the vapor body 24 and thence downwardly through the pipe 46. Likewise, as the pipe 46 is connected by the branch pipe 49 with the pipe 41, the solution eventually enters the latter and fiows downwardly into the communicatingcompartment 36 of the liquor box and then circulates upwardly for a third and final pass through the alining section of tubes, where it is further heated and the water evaporated to further concentrate the solution, into the companion vapor box compartment 46 of the vapor body and thence downwardly through the pipe 41 into the liquor box |4, when the concentration of the solution is completed to its desired final density. Inoperation,the thin liquoror solution is fed continuously into the evaporator and the concentrated-solution removed continuously from the evaporator through the discharge 22 located in the bottom of the last stage or final pass compartment 36 of the liquor box.

From the foregoing it will be understood that the solution circulating through the middle section of tubes during its first pass is of low density; the solution circulating through the front section of tubes during its second pass is of somewhat higher density; and the tubes contained in the rear or last circulating pass of the solution are the only ones filled with solution of the highest density. This construction results in rates of evaporation much higher than in the usual type of evaporator, in which all the heating surface is in contact with solution of the highest density, and due to the more efiicient utilization of the heating surface in the manner heretofore described it is possible to concentrate solutions to higher density in a minimum period of time. Another important advantage of this multiple-pass evaporator is that it operates continuously and at a uniform rate, thus equalizing the demands for steam to do the evaporating and water to condense the vapor.

' I claim as my invention:

An evaporator of the character described, comprising a heating unit including tubes for the circulation of liquor to be treated, a vapor box in communication with the upper ends of said tubes and having an inlet for introducing the liquor thereto, a receiver for the concentrated liquor communicating with the lower ends of said tubes and having a liquor-discharge, a vapor body disposed in communicating relation with said vapor box and having a liquid-receiving portion and a vapor receiving portion, a liquid deflector extending into said vapor body between its aforesaid portions and from that wall thereof adjoining its point of communication with said vapor box, means in said vapor box, said liquor-receiver and said vapor body for dividing such parts and the corresponding circulating tubes into compartments for the successive circulation of liquor therethrough, said deflector bridging the compartment-sections of the vapor body, and means for connecting the respective compartment-sections of the vapor body with those of the liquorreceiver,

BURTON S. HUGHES. 

